The present invention relates to an early tape end alarm for a multispeed tape recorder for giving an alarm to notify the immediate arrival of the tape end of a traveling tape before the tape end is reached.
It is desirable that an operator can previously know the end of a tape travel before the tape completes its travel. For example, in a case where a long time record is performed, if the apparatus issues an advance notice that the currently traveling tape will end in five minutes, the operator can prepare for the tape exchange before the tape running ends. Accordingly, a recording error due to a time required for tape exchange is minimized. If the notice is not issued, the operator frequently fails to find the timing of the tape exchange until the tape running terminates. If the remnant of the tape wound up by a hub is always observed, the tape exchange timing may be caught previously. Such an observation, however, is difficult or impractical.
One of the conventional early tape end alarm is used in a PHILLIPS type cassette tape recorder now marketed in Japan. In this known tape end alarm system, electric signals produced corresponding to a rotary speed of a reel shaft are compared with a given value. When those coincide with each other, an LED display is flashed. The given value is preset in accordance with a length of a tape used. Such a tape end alarm is useful for a case where it is used in a tape recorder operating with a single tape speed, such as the cassette tape recorder of the PHILLIPS type.
The conventional early tape end alarm is unfavorable for a tape recorder operable with two speeds like a microcassette type tape recorder. Let us consider a case where the given value is preset to five minutes before the tape end when the conventional device is used under an operating condition of 2.4 cm/s for the tape speed. In this case, when the tape speed is changed to 1.2 cm/s without changing the given value, the tape end alarm operation often fails, or the alarm is given immediately before the tape end. The time appropriate for the preparation for tape exchange is independent of the tape speed. Accordingly, the timing by which the tape end alarm is issued should be desirably independent of the tape speed.